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// -*- C++ -*- |
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// Copyright (C) 2005-2013 Free Software Foundation, Inc. |
// |
// This file is part of the GNU ISO C++ Library. This library is free |
// software; you can redistribute it and/or modify it under the terms |
// of the GNU General Public License as published by the Free Software |
// Foundation; either version 3, or (at your option) any later |
// version. |
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// This library is distributed in the hope that it will be useful, but |
// WITHOUT ANY WARRANTY; without even the implied warranty of |
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
// General Public License for more details. |
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// Under Section 7 of GPL version 3, you are granted additional |
// permissions described in the GCC Runtime Library Exception, version |
// 3.1, as published by the Free Software Foundation. |
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// You should have received a copy of the GNU General Public License and |
// a copy of the GCC Runtime Library Exception along with this program; |
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
// <http://www.gnu.org/licenses/>. |
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// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. |
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// Permission to use, copy, modify, sell, and distribute this software |
// is hereby granted without fee, provided that the above copyright |
// notice appears in all copies, and that both that copyright notice |
// and this permission notice appear in supporting documentation. None |
// of the above authors, nor IBM Haifa Research Laboratories, make any |
// representation about the suitability of this software for any |
// purpose. It is provided "as is" without express or implied |
// warranty. |
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/** |
* @file list_update_policy.hpp |
* Contains policies for list update containers. |
*/ |
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#ifndef PB_DS_LU_POLICY_HPP |
#define PB_DS_LU_POLICY_HPP |
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#include <bits/c++config.h> |
#include <cstdlib> |
#include <ext/pb_ds/detail/list_update_policy/lu_counter_metadata.hpp> |
#include <ext/pb_ds/tag_and_trait.hpp> |
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namespace __gnu_pbds |
{ |
/** |
* A list-update policy that unconditionally moves elements to the |
* front of the list. A null type means that each link in a |
* list-based container does not actually need metadata. |
*/ |
template<typename _Alloc = std::allocator<char> > |
class lu_move_to_front_policy |
{ |
public: |
typedef _Alloc allocator_type; |
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/// Metadata on which this functor operates. |
typedef null_type metadata_type; |
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private: |
typedef typename _Alloc::template rebind<metadata_type> __rebind_m; |
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public: |
/// Reference to metadata on which this functor operates. |
typedef typename __rebind_m::other::reference metadata_reference; |
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/// Creates a metadata object. |
metadata_type |
operator()() const |
{ return s_metadata; } |
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/// Decides whether a metadata object should be moved to the front |
/// of the list. |
inline bool |
operator()(metadata_reference r_metadata) const |
{ return true; } |
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private: |
static null_type s_metadata; |
}; |
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/** |
* A list-update policy that moves elements to the front of the |
* list based on the counter algorithm. |
*/ |
template<std::size_t Max_Count = 5, typename _Alloc = std::allocator<char> > |
class lu_counter_policy |
: private detail::lu_counter_policy_base<typename _Alloc::size_type> |
{ |
public: |
typedef _Alloc allocator_type; |
typedef typename allocator_type::size_type size_type; |
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enum |
{ |
/// When some element is accessed this number of times, it |
/// will be moved to the front of the list. |
max_count = Max_Count |
}; |
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/// Metadata on which this functor operates. |
typedef detail::lu_counter_metadata<size_type> metadata_type; |
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private: |
typedef detail::lu_counter_policy_base<size_type> base_type; |
typedef typename _Alloc::template rebind<metadata_type> __rebind_m; |
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public: |
/// Reference to metadata on which this functor operates. |
typedef typename __rebind_m::other::reference metadata_reference; |
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/// Creates a metadata object. |
metadata_type |
operator()() const |
{ return base_type::operator()(max_count); } |
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/// Decides whether a metadata object should be moved to the front |
/// of the list. |
bool |
operator()(metadata_reference r_data) const |
{ return base_type::operator()(r_data, max_count); } |
}; |
} // namespace __gnu_pbds |
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#endif |